1. Field of the Invention
The present invention relates generally to fluid flow regulators and more particularly to a novel high fluid flow rate regulator which embodies a unique arrangement for real time sensing of outlet flow rates and pressures and for providing a extremely rapid response to any small changes in the rate of flow of fluid through the outlet of the device.
2. Discussion of the Prior Art
Various types of fluid flow regulators have been suggested in the past. Generally these regulators comprise a casing having a fluid inlet and a fluid outlet, a pressure port disposed between the inlet and outlet, and a piston movable within the casing in response to fluid pressure exerted thereon. When fluid pressure is applied to the pressure sensing face of the piston it will move into a port closing position against the urging of a spring. When the piston is in a port open position, fluid flows from the inlet, through the pressure port and outwardly through the outlet at a predetermined reduced pressure. Typically a portion of the fluid at a predetermined reduced pressure flowing through the outlet passage of the regulator is redirected through one or more small bores or pressure pick-ups formed in the walls of the outlet passageway. This fluid then flows through a conduit interconnecting the small bores with a pressure chamber which is located between a wall of the casing and the pressure sensing face of the movable piston. This redirected fluid impinges upon the piston face, which often is relatively small, and urges the piston in a direction toward a port closing position. In this way the device regulates the fluid flow through the regulator. The pressure pick-up bores formed in the outlet passageway of the prior art regulators generally extend radially outwardly at right angles to the direction of flow of the fluid.
In applications wherein fluid pressures and flow values are relatively low and where precise control of outlet flow rates is unnecessary, prior art devices of the aforementioned character preform satisfactorily. However, in high pressure, high volume applications requiring precise and instantaneous control of fluid flow rates, such prior art devices are unacceptable. Specific drawbacks of these prior art fluid flow regulators include relatively small pressure ports, small pressure sensing faces on the reciprocating pistons of the devices and poor pressure pick-up locations and configurations. For example, radially extending pressure pick-up bores located in the outlet passage of the regulator, as found in many prior art devices, have several disadvantages. Such configurations encourage detrimental aspiration effects, cause difficulties in calibration and markedly contribute to slow response times.
As will become apparent from the discussion which follows, the unique design of the fluid flow regulator of the present invention effectively overcomes the drawbacks of the prior art devices. The regulator of the present invention has both a large pressure port and a large cooperating port closure means presenting a large pressure sensing face. Further, the regulator embodies a highly novel ram pressure pick-up arrangement. These unique features combine to produce a precision regulator capable of accommodating high pressures and high fluid flow rates while at the same time providing very accurate and virtually instantaneous response to very small outlet flow rate changes.
Applicants are familiar with a line of fluid flow regulators manufactured by the Futurecraft Corporation of City of Industry, California, which regulators are illustrated in a catalog published by said Company and which represent the most pertinent art known to applicants.